1350-1400;Middle English < Late Latinrādīcālis having roots, equivalent to Latinrādīc- (stem of rādīx) root1 + -ālis-al1

Related forms

radicalness, noun

half-radical, adjective

half-radically, adverb

multiradical, adjective

nonradical, adjective, noun

nonradicalness, noun

quasi-radical, adjective

quasi-radically, adverb

semiradical, adjective

semiradically, adverb

semiradicalness, noun

subradical, adjective

subradicalness, noun

superradical, adjective

superradically, adverb

superradicalness, noun

ultraradical, adjective, noun

ultraradically, adverb

unradical, adjective

unradically, adverb

Synonyms

1. basic, essential; original, innate, ingrained. 2. complete, unqualified, thorough; drastic, excessive, immoderate, violent. Radical,extreme,fanatical denote that which goes beyond moderation or even to excess in opinion, belief, action, etc. Radical emphasizes the idea of going to the root of a matter, and this often seems immoderate in its thoroughness or completeness: radical ideas; radical changes or reforms.Extreme applies to excessively biased ideas, intemperate conduct, or repressive legislation: to use extreme measures.Fanatical is applied to a person who has extravagant views, especially in matters of religion or morality, which render that person incapable of sound judgments; and excessive zeal which leads him or her to take violent action against those who have differing views: fanatical in persecuting others.

late 14c., in a medieval philosophical sense, from Late Latin radicalis "of or having roots," from Latin radix (genitive radicis) "root" (see radish). Meaning "going to the origin, essential" is from 1650s. Radical sign in mathematics is from 1680s.

Political sense of "reformist" (via notion of "change from the roots") is first recorded 1802 (n.), 1817 (adj.), of the extreme section of the British Liberal party (radical reform had been a current phrase since 1786); meaning "unconventional" is from 1921. U.S. youth slang use is from 1983, from 1970s surfer slang meaning "at the limits of control." Radical chic is attested from 1970; popularized, if not coined, by Tom Wolfe. Radical empiricism coined 1897 by William James (see empiricism).

n.

1630s, "root part of a word, from radical (adj.) Political sense from 1802; chemical sense from 1816.

A group of atoms that behaves as a unit in chemical reactions and is often not stable except as part of a molecule. The hydroxyl, ethyl, and phenyl radicals are examples. Radicals are unchanged by chemical reactions.